/usr/lib/python3/dist-packages/bson/ is in python3-bson 3.6.1+dfsg1-1.
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/usr/lib/python3/dist-packages/bson/__init__.py
/usr/lib/python3/dist-packages/bson/binary.py
/usr/lib/python3/dist-packages/bson/code.py
/usr/lib/python3/dist-packages/bson/codec_options.py
/usr/lib/python3/dist-packages/bson/dbref.py
/usr/lib/python3/dist-packages/bson/decimal128.py
/usr/lib/python3/dist-packages/bson/errors.py
/usr/lib/python3/dist-packages/bson/int64.py
/usr/lib/python3/dist-packages/bson/json_util.py
/usr/lib/python3/dist-packages/bson/max_key.py
/usr/lib/python3/dist-packages/bson/min_key.py
/usr/lib/python3/dist-packages/bson/objectid.py
/usr/lib/python3/dist-packages/bson/py3compat.py
/usr/lib/python3/dist-packages/bson/raw_bson.py
/usr/lib/python3/dist-packages/bson/regex.py
/usr/lib/python3/dist-packages/bson/son.py
/usr/lib/python3/dist-packages/bson/timestamp.py
/usr/lib/python3/dist-packages/bson/tz_util.py